'______________________________________________________
'                    LINQ 2: Using Calculations
'                                 Ron Kessler
'                                    2/9/09
' _______________________________________________________
' 


' Make sure to look at the tables I use in my Object Designer and add them.
' This form shows how to grab data, make sure it is not null and if so put in a
' 0 in that column. Also shows how to make a calculation in a column.

' Introduces Lambda expressions & Nullable types

' Step 2: Look at the paging.aspx form. Make it the Startup form remember!

Partial Class _Default
    Inherits System.Web.UI.Page

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Dim dc As New AdventureWorksDataContext
        '---in C# use Select New With (we are creating a new object)
        Dim products = From p In dc.Products _
                              Where p.ProductCategory.Name = "Mountain Bikes" _
                              Select New With {.Product_ID = p.ProductID, _
                                .Product_Name = p.Name, _
                                .Order_Count = p.SalesOrderDetails.Count, _
                                .Total_Sales = _
                                    String.Format("{0:c}", If(p.SalesOrderDetails.Sum(Function(s) CType(s.OrderQty, Double?) * CType(s.UnitPrice, Double?)), 0))}
        '---the Function keyword is like the "=>" in C#.
        '---the If method above is new. If the expression to the right of If = null, then we tell it to use 0 instead.

        GridView1.DataSource = products
        GridView1.DataBind()

    End Sub
End Class